1. Field of the Invention
The present invention relates to a pixel structure of a liquid crystal display panel and method of making the same, and more particularly, to a pixel structure of a wild viewing angle liquid crystal display panel and method of making the same.
2. Description of the Prior Art
As the requirement of flat TVs increases, liquid crystal displays (LCDs) have become the most popular product in flat TV market. In particular, wild viewing angle LCD is a critical technique to develop in LCD industry. Please refer to FIGS. 1-2. FIGS. 1-2 illustrate a conventional pixel structure of an LCD panel, where FIG. 1 is a top view of the pixel structure, and FIG. 2 is a cross-sectional view of the pixel structure shown in FIG. 1 along a tangent line AA′. As shown in FIGS. 1-2, the conventional pixel structure of an LCD panel includes a substrate 10 having a switch device region 12, a display region 13 and a peripheral region 14 defined thereon. In the switch device region 12 disposes a thin film transistor, which includes a semiconductor layer. The semiconductor layer includes a channel region 16, a source region 18 and a drain region 20 disposed on two opposite sides of the channel region 16, and two lightly doped drains (LDDs) 22. One LDD 22 is disposed between the source region 18 and the channel region 16, and the other LDD 22 is disposed between the drain region 20 and the channel region 16.
The semiconductor layer is covered with a first insulating layer 24, and a first patterned conductive layer is disposed on the first insulating layer 24. The first patterned conductive layer includes a scan line 26 disposed in the peripheral region 14, and a gate electrode 28 disposed in the switch device region 12 and electrically connected to the scan line 26. The first insulating layer 24 and the first patterned conductive layer are covered with a second insulating layer 30, and a second patterned conductive layer is disposed on the second insulating layer 30. The second patterned conductive layer includes a data line 32 disposed in the peripheral region 14, and a drain pad 34 disposed in the switch device region 12. The second insulating layer 30 and the first insulating layer 24 expose the source region 18 and the drain region 20, so that the data line 32 may be electrically connected to the source region 18, and the drain pad 34 may be electrically connected to the drain region 20.
The prior art pixel structure includes a third insulating layer 36, a common electrode 38, a fourth insulating layer 40, and a pixel electrode 42. The third insulating layer 36 is disposed on the second insulating layer 30, the data line 32 and the drain pad 34. The common electrode 38 is disposed on the third insulating layer 36. The fourth insulating layer 40 is disposed on the common electrode 38 and the third insulating layer 36. The pixel electrode 42 is disposed on the fourth insulating layer 40, and electrically connected to the drain pad 34.
The conventional pixel electrode of an LCD panel, however, suffers from the following drawbacks. The common electrode 38 and the data line 32 are made of different material layers, and therefore require the third insulating layer 36 of a quite large thickness disposed therebetween to avoid shot-circuiting. This extra insulating layer increases the process complexity, and influences the transparency of the LCD panel.
In case the third insulating layer 36 is omitted, the data line 32 and the common electrode 38 formed subsequent to the data line 32 are in the same level. In such a case, the distance between the data line 32 and the common electrode 38 must be large enough to avoid short-circuiting, but this large distance between the data line 32 and the common electrode 38 reduces the aperture ratio.